Heat transfer printing (also known as thermal transfer printing) is the process of transferring images from one substrate to another by the application of heat. The image may first be applied to a first substrate, for example, a polymeric film, this image then brought into contact with a target substrate, e.g. a metallic film, glass or fabric, and heated. The target substrate and the first substrate may then be separated, leaving the image (in reverse) on the target substrate.